Polyamines may influence phytochelatin synthesis during Cd stress in rice

Abstract

Highlights Putrescine pre-treatment increased cadmium toxicity in rice.  In contrast, putrescine synthesis inhibition alleviated cadmium stress.  The synthesis of higher polyamines and phytochelatins is antagonistically related.  Putrescine may decrease phytochelatin synthesis at enzymatic and gene expression levels. Although the metabolism of phytochelatins and higher polyamines are linked with each other, the direct relationship between them under heavy metal stress has not yet been clarified. Two approaches were used to reveal the influence of polyamine content on cadmium stress responses, particularly with regard to phytochelatin synthesis: putrescine pre-treatment of rice 2 plants followed by cadmium stress, and treatment with the putrescine synthesis inhibitor, 2-(difluoromethyl)ornithine combined with cadmium treatment. The results indicated that putrescine pre-treatment enhanced the adverse effect of cadmium, while the application of 2-(difluoromethyl)ornithine reduced it to a certain extent. These differences were associated with increased polyamine content, more intensive polyamine metabolism, but decreased thiol and phytochelatin contents. The gene expression level and enzyme activity of phytochelatin synthase also decreased in rice treated with putrescine prior to cadmium stress, compared to cadmium treatment alone. In contrast, the inhibition of putrescine synthesis during cadmium treatment resulted in higher gene expression level of phytochelatin synthase. The results suggest that polyamines may have a substantial influence on phytochelatin synthesis at several levels under cadmium stress in rice. Abstract

Factors playing role in heat acclimation processes in barley and oat plants

“…However, some plants accumulate polyamines, others have constant or even lower endogenous polyamine content when exposed to stress. Recent studies support the view that the more polyamine the better theory cannot be generalised (Pál et al 2017). Under the present experimental conditions, heat treatment significantly reduced the contents of the major polyamines.…”

Interactions between plant hormones and thiol-related heavy metal chelators

“…to be protective against Cd stress in rice. PUT pre-treatment decreased the content of thiols and PCs, the activity of PCS and even on the gene expression level of PCS (Pál et al 2017). The decrease in PC may be resulted from the depletion of GSH content due to the increased PA metabolism.…”

“…Acting as signalling molecules in a highly complex relationship, these molecules allow plants to retain growth plasticity during development and are probably the main means by which plants respond to abiotic and biotic stresses (Bücker-Neto et al 2017). Both their increased endogenous levels under heavy metal stress and the relationship between their modified endogenous content (resulted from genetic modification or exogenous treatment) and the level of heavy metal tolerance have been reported in various plant species (Xiang and Oliver 1998;Groppa et al 2001;Maksymiec andKrupa 2002, Hsu andKao 2003;Maksymiec et al 2005;Wen et al 2010a;Tao et al 2013;Chmielowska-Bąk et al 2013;Kovács et al 2014;Gondor et al 2016;Pál et al 2017). Majority of the experimental data focuses on the changes in growth and photosynthesis parameters, the induction of antioxidant system or the relationship between the observed protective effect and the hormonal changes.…”

Molecular background of cadmium tolerance in Rht dwarf wheat mutant is related to a metabolic shift from proline and polyamine to phytochelatin synthesis

“…Increased contents of PA, especially PUT, and proline have been reported in soybean after Cd stress, but these did not prevent Cd-induced changes in nitrogen assimilation pathways and the Cd stress response (Balestrasse et al 2005). In addition, it has been demonstrated in rice that during Cd stress, PAs may have a substantial influence on PC synthesis, as exogenous PUT inhibited both the activity and the gene expression level of PCS (Pál et al 2017). SPD is synthesised from PUT through the addition of an aminopropyl moiety donated by decarboxylated Sadenosylmethionine and catalysed by SPD synthase, while adding an additional aminopropyl moiety to SPD produces SPM with the help of SPM synthase (Liu et al 2015).…”

“…The interaction between the compounds analysed (proline, PCs and PAs) and plant hormones (Pál et al 2015(Pál et al , 2017(Pál et al , 2018a makes the picture even more complex. SA synthesis starts from chorismate, as a precursor, which after, the synthesis pathway is branching to two separated pathways.…”